actually, it is not a good idea. The stock wiring is not rated for the added load, and will eventually (if not right away) fail

Mount whatever lights you want to use on the trailer, and then run a suitable size positive wire to the front, along with either a new ground wire, or upgrading the existing ground to acomodate the new load on it. The connector can either be replaced with one that has 1 more contact (or more, 2 if you want a seperate ground for the lights), or just keep your existing connecter and add another for the reverse lights (that would be the best way if you use more then 1 vehicle to tow the trailer, or loan it out on occasions...saves on the hassle of hacking connectors togethor)

To run those new lights off of the tow vehicle, run a positive wire from the battery (underhood fuse box is just as good, and usaully easier to connect to), through a circuit breaker or fuse, then through a relay, and then to the back of the vehicle. Use the factory reverse light circuit (or just a rocker switch) to energize the relay. Could also do both. The switch would be handy to have light that isnt blocked by the trailer when setting up camp, or whatever else you may be doing.

i used that back up light that autozone sells which comes with 2 clear lights about 5 inches wide and 2 tall. i mounted them to the cornors of my trailer and tapped into the reverse lights on my truck (07 silverado). we also hooked up the wire to my jeep and also my uncles 06 dodge ram so he could use it also since we both tow the trailer alot and none of the truck have had a prob. also i did that about 5 years ago and have used them countless times one of the best things i did. but you do it what ever way makes you feel comfortable because its your truck. hope this helps.

http://www.autozone.com/autozone/acc...fier=9749_0_0_
thease are not the exact same ones i used but close. all i ran was 1 extra wire from the light on trailer up to the truck and connected it to the wire behind my taillight. the ground wire i just screwed to the trailer since it is allready grounded. easy fix took less than an hour and the light are 55 watts so they light up a good distance and its a wide beam of light.

but being projectors they don't really have a visible reflector. meaning you may not have to cover them when on the road and underway.

generally speaking, jonnylaw don't like it when he pulls up behind you on the road and see's his own headlights reflecting brightly back at him - or worse if he lights you up with his take-downs or door spot lights and blinds himself...

How do I know?

I had a friend that mounted a massive ~6" x ~9" off road light in the rear deck of his old school VW GTI because the oem reverse lights were those tiny triangles... even though it was wired off of a relay and only turned on when the car was in reverse, it netted him a traffic citation...

you could run a switched wire (or from your truck's existing reverse lights) like mentioned above, to a relay that then turns the power on to your rear-directed fog/driving lights. you could do an easy quick-connect or a basic plug/harness concoction to make it easy to connect and disconnect when you want to. it doesn't really matter what plug you're using, or how many wires it was meant for, you will only be using one(or two).

and as for the reflectors from the housing being a bad idea, i second that as well. i personally have some LED driving lights that can just be tapped into the parking lights onto my truck. they are such a low power draw, it's a non issue. going with an led enclosure also removes/minimizes the chance of the 5-0 getting upset about a refracted beam.

I didn't know about five-o getting upset about the reflector in the lens. That's good to know. I'd be pissed to spend money on lights, then get a ticket and have to replace the lights with something DOT approved.

I don't mind a little expensive. I'm going to have this trailer a LONG time. I just didn't want to spend a lot of cash on lighting and not have it help.

I like the round ones. Being surface mounted I can get rid of the Jeep style lights on the back that I keep breaking. My 4' dove tail is nice but it is hard on exposed taillights. At $40 a pop I wouldn't be happy to keep breaking them.

i Hooked some led reverse lights on an older trailer we had. My truck at the time only had the 4 prong wire connector. I wired another connector with weatherpack teminals and used a seperate switch with led indicator. Sometimes its nice to have the lights on when the vehicle is not in reverse. Like in park on a hill or driving around your property, loading up stuff at night, or other times when you dont want the vehicle idling. I just had a 3/4" bright red led indicator light on the dash next to the switch so i wont forget they are on when driving down the road.